How to Adjust a Stiff Brake Pedal on an Air Brake Master Cylinder?

[DiAubree]

First, check if the brake pads are excessively worn. Inspect the master cylinder and wheel cylinders for internal leaks. The most common reason for brakes becoming soft is moisture in the brake fluid, so you can visit a repair shop to have the moisture in the brake lines removed.

[SanGabriela]

I used to drive long-haul trucks, and the brake pedal was as hard as a block of iron, extremely difficult to press. That time I tried adjusting it and found it was caused by the brake clearance being too small. The steps are simple: first, check the air pressure gauge to ensure it's within the normal range, say 7-8 bar, and inflate if insufficient. Then lift the vehicle, locate the adjustment arm of the rear wheel brake, and use a wrench to turn the nut, loosen it one turn and test the pedal again. If it's still hard, it might be due to a blocked pipeline or a faulty master cylinder valve, requiring lubrication or replacement. Remember, don't force the adjustment for too long; if you feel unstable, immediately seek a professional repair shop. Safety comes first—this issue increases the risk of rear-end collisions while driving. I always recommend regular maintenance of the braking system.